Drug testing

The Four Seasons called today to say, essentially - stop calling. I've been pestering the HR woman about whether they'd gotten the results of my Monday drug test. No.
The whole issue is humorous; drugs have little appeal to me, so the issue is moot. But the culinary field is loaded with burners (plenty of my classmates are drug parolees), so I understand the issue. But it's delaying the start of my externship, so I'm antsy. Shouldn't they be able to turn around those results in 72 hours?